Some patterns constituting a large-scale integrated circuit (LSI), as exemplified by DRAM of a gigabit class, have a minimum design rule reduced from submicron up to the order of nanometer. One of major causes for reduced yields in a manufacturing process of such an LSI includes defects contained in a reticle (also called a mask) used when a hyperfine pattern is exposed and transcribed onto a semiconductor wafer using lithography technology.
With increasingly finer pattern dimensions of LSI formed on a semiconductor wafer, dimensions in which such pattern defects must be detected are also becoming extremely smaller. Thus, reticle defect inspection apparatuses for inspecting for extremely small defects are vigorously being developed (for example, JP-A 2006-98156 (KOKAI)).
One method of improving performance of an exposure device to a semiconductor wafer is to make wavelengths of a light source shorter. Thus, DUV (Deep Ultra Violet) light having short wavelengths, for example, a light of the wavelength 193 nm using an ArF laser is used as the light source of an exposure device. In addition, to further enhance resolution, using EUV (Extreme Ultra Violet) light, for example, a light of the wavelength of about 13.5 nm using plasma emission is also being examined.